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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 43 · 40 questions
TalentJR

The trick (Seventh times eleven): A leapfrog list: start with two numbers, then each number is the sum of the two before it, up to 10 numbers. Find the 7th number. Multiply it by 11 (the number with a 0 on the end, plus the number): that is the total of all 10.

NameDateTime takenScore ___ / 40
  1. 1.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  3. 3.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  6. 6.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  7. 7.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  9. 9.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  14. 14.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  15. 15.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  18. 18.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  19. 19.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  21. 21.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  22. 22.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  24. 24.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  29. 29.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  32. 32.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  35. 35.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  37. 37.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  40. 40.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?

Answer key

  1. 847
  2. 143
  3. 1287
  4. 407
  5. 1034
  6. 715
  7. 792
  8. 869
  9. 1122
  10. 726
  11. 781
  12. 286
  13. 572
  14. 561
  15. 693
  16. 649
  17. 407
  18. 286
  19. 671
  20. 473
  21. 308
  22. 539
  23. 539
  24. 880
  25. 1199
  26. 539
  27. 451
  28. 759
  29. 1023
  30. 506
  31. 825
  32. 198
  33. 605
  34. 550
  35. 594
  36. 1001
  37. 704
  38. 308
  39. 1001
  40. 814

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